Photoalignment at the nematic liquid crystal–polymer interface: The importance of the liquid crystalline molecular structure

Polymer–Nematic Liquid Crystal Interface: On the Role of the Liquid Crystalline Molecular Structure and the Phase Sequence in Photoalignment

“…to confirm the role of the presence/absence of the offset stacked aromatic interactions between the NLC and the photosensitive polymer, postulated recently [ 17 ];…”

“…In contrast to that, the thiocyanate (SCN) group in 6CHBT does not change significantly the MESP of the phenyl ring compared to the cyano-group in 8CB. Therefore, in this respect, 6CHBT can be regarded very similar to the benzonitrile containing PCH LC homologous series discussed very recently [ 17 ].…”

“…The choice of the NLC compounds has been motivated by the main goals of the present work, namely: to confirm the role of the presence/absence of the offset stacked aromatic interactions between the NLC and the photosensitive polymer, postulated recently [ 17 ]; to get further insights in the role of the molecular structure of the NLC in photoalignment processes; to find out how the pretransitional fluctuations near the nematic-to-smectic A phase transition temperature influence the photoalignment. …”

“…Furthermore, it has also been shown that the mechanism of the photoalignment depends on the liquid crystalline molecular structure: the photocontrol of LCs with biphenyl rigid cores substantially differs from that of LCs not having biphenyl group in the molecular structure. The differences have been phenomenologically explained by the presence/absence of the offset stacked aromatic interactions between the rigid core of the LCs and the azobenzene moiety of the interfacing polymer [ 17 ].…”

“…In particular, we investigate a compound where one of the phenyl group has been modified with three fluorene atoms at 3,4,5 positions, which almost “invert” the molecular electrostatic surface potential (MESP) of the ring [ 18 ]. Additional test measurements have been also performed on a LC compound having similar molecular structure to the PCH homologous series investigated in our previous publication [ 17 ]. The third LC which we investigate is a cyanobiphenyl compound, exhibiting a nematic-to-smectic A phase transition at a temperature .…”